One of the most rewarding experiences, often cited by Managers, is to watch your people flourish in their professional endeavours. BUT to this I would add that even more rewarding is being witness to their personal growth and development.
Being able to connect beyond the professional and into the personal creates a leadership relationship wherein reciprocation is Queen; those you lead will do more than you had ever anticipated or expected, for you.
The one way highway of Manager-Employee is tumbleweed across the dusty plains of old school management. Make way for the super highway of today's successful Leaders who see beyond the iron fist of driving Employee production while ignoring the true sources of Employee engagement.
Consider the time you invest (daily, weekly, monthly, etc.) to build your relationships to be equivalent to growing Employees that require very little supervision and little to no 'rah rah' motivation. Consider what that means for you as the Manager?